Electric meter.



No. 698,643; PatentedApr, 29, I902.

T. DUNCAN.

ELECTRIC METER. (Ap alication filed Aug. 24. 1898.)

(No Model.) 2 Sheats-Sheet l.

Wh W h ;8

No. 693,643. Pafented Apr. 29, I902,

T. DUNCAN.

ELECTRIC METER.

(Application filed Aug. 2%, 1898.

2 Sheets Sheat 2.

No Model.)

TRANS/.4 T/(VG DE V/CES 29W 1 W-GQM. a5 mwww s THE "cams PETERS cairnordm'uon WASHINGTON, o. c

NITED STATES PATENT OFFICE.

THOMAS DUNCAN, OF FORT WAYNE, INDIANA, ASSIGNOR TO THE SIEMENS & HALSKE ELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

ELECTRIC METER.

SPECIFICATION forming part of Letters Patent No. 698,643, dated April 29, 1902 Application filed August 24,1898. Serial No. 689,409. (no model.)

To all whom it may concern.- Figure 1 is a view in elevation of one form 50 Be it known thatI, THOMAS DUNCAN, aciti-' of my improvement with the series coil and zen of the United States, residing at Fort volt-coils shown in vertical central section. Wayne, in the county of Allen, in the State Fig. 2 is a similar view showing two series of Indiana, have invented certain new and coils arranged upon oppositesides of the aruseful Improvements in Electric Meters; and mature and also showing a modified arrange- 5 5 I do hereby declare that the following is a ment of the volt-coils, which are shown in verfull, clear, and exact description of the inven' tical, section. Fig. 3 is a plan view of one tion, which will enable others skilled in the form of my improvement, showing the relaart to which it appertains to make and use the tive position of the series coil, volt-coil, and

same, reference being had to the accompanycore and the retarding-magnet. Fig. 4: illus- 6o ing drawings, which form part of this specifitrates another modified arrangement, being cation. an efficient form in which two volt-coil cores This invention relates to improvements in are employed with their magnetizing-coils,

I 5 integrating induction motor-meters, and parand the series coils are shown in vertical secticularly to the class of meters-employed for tion. Fig. 5 is a vector diagram for illustrat- 65 the measurement of lagging currents. ing the electrical principles involved.

The object of the present invention is to In my improvement I employ the following provide a simple and efficient type of meter elements: a source of alternating currents 2,

that will measure both inductive and non-in a series coil or coils 6, volt-coils 14., a lamiductive loads with equal accuracy andwhose nated iron core 17, a retarding-coil 19 for lag- 70 cost of manufacture can be materially reging the phase of the magnetism which travduced or' lessened by eliminating the impeerses the said core 17, a variable resistance in dance-coil employed in other meters of this series with the said retarding-coil, an aluclass. v minium disk armature 7, mounted upon a In in'duction-wattmeters it is a common supporting-spindle 8, a permanent magnet 75 practice to employ an impedance-coil as an 13, a step or jewel supporting said spindle, extra or auxiliary element in series with the and a suitable registering mechanism 12. shunt or volt field-coil to produce a lag of the In a former application, filed by me on the current through the said volt field-coil to as 9th day of August, Serial No. 688,163,I have near ninety degrees behind the electromoshown'anddescribed a form of motor-meter 8o tive as is possible to enable the meter to in which the impedance-coil as a separate or measure inductive loads. In the presentirndistinct element is eliminated and which difp'rovem'ent I have dispensed with the impefers from the present application in this, that 3 5 dance-coiland so constructed thevolt field-coil in saidapplication the requisite phase angle that it performs the usual functions of both of ninety degrees is obtained by utilizing the 85 the impedance and volt coils-i. 6., it proreluctance and hysteresis of a solid magnetic duces a magnetic field that is lagging ninety core in cooperative relation with a suitable degrees or is in quadrature with the electrovolt coil or coils, whereas in the present im- 40 motive force which it represents. provement I employ a laminated iron core It is now well understoodin the art that an having the least possible reluctance and hyso induction-wattmeter must have the magnetteresis in cooperation with a volt'coil or coils ism which represents the pressure lagging andan additional or auxiliary coil mounted behind said pressure by ninety degrees to enupon the said laminated iron core for lagging able the torque to be proportional to the real or retarding its magnetism to ninety degrees.

or true energy, and it need not, therefore, be In describing the improvement with refer- 5 described in detail. ence to Fig. 1 the series coil 6 is placed in the In the accompanying drawings similar refmain line 3 and is traversed by the current erence-numerals indicate like parts. supplied to the translating devices 5 from the generator 2 by means of the circuit leads or mains 3 and 4. The magnetism of the coil 6 will vary in strength and phase angle with the current supplied to the translating de vices 5. A revoluble aluminium disk armature 7 is suitably mounted upon a spindle 8 and in inductive relation to the series coil 6. To produce a magnetic field that is representative of the electromotive force of the mains 3 and 4 and lagging ninety degrees behind the same, I employ the laminated iron core 17 and mount in any convenient manner thereon the volt-coils 14, adapted to receive current from the mains in shunt or multiple by means of the wires 15 and 16. The current through the coils 14, however, cannot lag ninety degrees on account of their ohmic resistance, and since the magnetism is approximately in phase with the current through the coils 14 it must also be less than ninety degrees; but to obtain this desired lag of ninety degrees or quadrature I employ a retardingcoil 18 to lag or retard the passage or phase of the magnetism through the core 17.

If the impedance of the volt-coils 14 is sufficient to lag the current and magnetism, say, eighty degrees, the requisite ninety degrees is obtained by adjusting the resistance 19 in series with the retarding-coil 18.

The revoluble disk armature is actuated by the shifting magnetic field that is established by the combining of the lines of force of the coil 6 and the core 17 into a common resultant, and thereby exerting a torque that is proportional to the real watts or amperes volts cosine of the angle of lag between the current and electromotive force.

To -enable the speed of the meter to be proportional to the torque and watts, a perma-- nent magnet 13 is so arranged as to embrace between its poles'the revolu ble disk armature in a Well-understood manner.

In calibrating the meter the resistance 19 is decreased if the speed is slow on inductive loads, and if found to be running too fast on lagging currents the resistance 19 is increased.

The use of a closed secondary circuit, such as the coil 18, in conjunction with another magnetizing-coil for the purpose of retarding or lagging the phase of magnetism of the said magnetizing-coil, has been in use for a number of years. I therefore do not claim such a construction broadly, but simply in combination with a combined impedance-coil and volt-coil to reduce the cost of meters and still enable them to accurately measure inductive loa s.

The laminated iron core 17 is shown as resembling the letter C in form; but any other formmaybe employed that willassistin giving a good impedance and conform to the varied tastes of designers or constructors. This core has an opening or gap upon one side of sufficient width to admit of the armature 9 without contact therewith.

The revolutions of the armature are com- .each core.

municated to the registering-train 12 by means of the spindle 8, worm 10, and worm-wheel 11 in the usual manner.

Fig. 2 shows the employment of two series coils 6 and shows the retarding-coils 18 mounted or wound upon the poles of the core 17.

In Fig. 3 is shown a variable rheostat or resistance 19 for regulating the phase of the magnetism through the core 17, as set forth.

In Fig. 4 is shown a very efficient form of my improvement, in which two volt-coil coils 17 are used, with their energizing volt-coils 1 1, four in number, wound thereon and two series field-coils 6 arranged upon opposite sides of the revoluble armature. To adjust the phase of the magnetism through the cores 17, a lagging-coil 18 is shown arranged upon The coil 18 can be adjusted separately or may be connected in series. The latter connection is notshown in the drawings, as it is one that would readily suggest itself to any one versed in the art.

In Fig. 5 I have shown by vector diagram the various phase positions of the current and pressures involved. The line 0 a represents the direction of the impressed electromotive force, the line 0 0 represents the current flowing in the coil 14, the line ob represents the current flowing in the coil 18, and the two components 0 b and 0 c combine to form a resultant current 0 d, which represents in magnitude the impressed pressure, but is displaced therefrom ninety degrees, due to the auxiliary phase-changing devices employed. The line 0 d is in quadrature with the impressed pressure 0 a.

What I desire to secure by Letters Patent 1s 1. The combination in an induction motormeter of a series field-coil; a combined pressure magnetic field and impedance device comprising a laminated iron core with a lowreluctance air gap and magnetizingcoils mounted upon both sides of said air-gap and upon the adjacent poles of said iron core forming said air-gap; a metallic disk armature revoluble between the poles of and in the airgap of said iron core;- a secondary circuit receiving currents by induction from the said combined pressure magnetic field and impe dance device; a variable resistance in series with said secondary circuit; a retarding magnetic field governing the revolutions of said armature; and means for registering the revolutions of said armature.

2. The combination in an induction motormeter, of a combined pressure magnetic field and impedance device provided with magnetizing-coils mounted thereon, a revoluble armature inductively associated with said device, a secondary circuit receiving current by induction from said device, means for varying the current in said secondary circuit, series field-coils also inductively associated with said revoluble armature, the magnetic influence of said series field-coils and said pres sure magnetic field-coils acting upon the armature in different areas, substantially as described.

3. The combination in an induction motormeter, of series field-coils, a combined pressure magnetic field and impedance device, provided with magnetizingcoils mounted thereon, a revoluble armature inductively as sociated With said device and said series fieldcoils, a secondary circuit receiving current by induction from said device, a variableresistance in circuit with said secondary circuit, and a retarding magnetic field governing the revolutions of said armature, the said series field-coils and said combined pressure magnetic field-coils acting upon the armature in different areas, substantially as described.

4. The combination in an induction motor meter, of series field-coils, a combined pressure magnetic field and impedance device comprising an iron core with a low-reluctance air gap, provided with magnetizing coils mounted thereon, a revoluble armature inductively associated with said device and said series field-coils, a secondary circuit receiving current by induction from said. device, a

variable resistance in circuit with said second- Witnesses:

,ADELAIDE KEARNS, WATTS P. DENNY. 

